Parkinson disease (PD) is the second most common, chronic, progressive, neurodegenerative disease worldwide and is considered a treatable and manageable disorder with an armamentarium of effective medical, surgical, and physical therapies available. Nonetheless, the dopamine precursor, levodopa, remains the standard of therapy for PD.1 As the disease progresses, however, and the severity of dopamine depletion increases, the duration of efficacy of levodopa therapy progressively shortens, giving rise to fluctuations in response. Motor fluctuations can manifest as a wearing-off effect, dyskinesias, or an unpredictable on-off response with sudden freezing. Almost 40% of patients will experience motor fluctuations after 4 to 6 years of treatment, which will increase to at least 70% after long-term treatment (>9 years).2 This finding is even more striking in patients with young-onset PD (symptom onset before 40 years of age), who have a reported 90% prevalence of dyskinesias and motor fluctuations 5 years after initiation of levodopa therapy.3
Boyle A, Suescun J, Schiess MC. Opicapone: A Novel Adjunct for an Old Standard. JAMA Neurol. 2017;74(2):153–154. doi:10.1001/jamaneurol.2016.5012
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